Question: $ { {-1} \times \left[\begin{array}{rr}{3} & {4} \\ {-1} & {-1}\end{array}\right] = {?} } $
Answer: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-1}\times{3} & {-1}\times{4} \\ {-1}\times{-1} & {-1}\times{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {-4} \\ {1} & {1}\end{array}\right]}$